1. Field of the Invention
This invention relates to shooting training and relates particularly but not exclusively to training of military or other personnel with regard to shooting.
2. Description of Related Art
Shooting training for military personnel or other personnel requires highly varied and complex scenarios. In particular, training in night shooting is a particularly challenging endeavour. A common prior art approach comprised locally illuminating a target with a soft light that simulates moonlight. Typically, such soft light was coloured blue so that it did not appear as a bright colour. Trainee marksmen use their natural eyesight unaided with any vision enhancing apparatus. Typically, in a range used for the early examples of night shooting, targets were placed at particular positions simulating an offensive area. This included placing the targets in open paddocks or fields, or placing targets in a simulated village environment. The trainee marksmen then walked through the offensive area on the range and a range controller person activated the blue lights to provide soft lighting to discreet ones of the targets. Some of the targets may have included an image depicting an expected offensive image such as an attacking soldier or other like person who might provide confrontational aggressive response. Other expected images comprise images of children or women who are passive and not aggressive. Other images comprised pictures of offensive vehicles such as tanks or armoured personnel carriers. In these early prior art ranges, there was a distinct problem, in that there is a natural ambient light even at night time and the trainee marksmen is able to visually ascertain the location of the targets with the unaided human eye. Thus, any surprise element of a target image suddenly appearing was minimised, particularly for the trainee marksman who has a keen eye.
In other examples, a target range has been provided where there is a row of targets at a target firing location, and a remote infrared (IR) projector located at a position of trainee marksmen who are usually positioned in a bunker or like location. In such cases, the trainee marksmen wear IR night vision imaging equipment such as IR goggles. In some cases the marksmen can use similar night vision apparatus such as thermal or IR imaging monocular or binocular or weapon sighting devices. In such an environment, the trainee marksman knows the position of the targets, and the position of the projector, and is able to pre-ascertain the likely location of a particular target image. Further, because the IR projector has been positioned with the marksmen, the IR light beam, IR illuminates dust particles in the air as it travels to illuminate the targets. The marksmen are able to see a beam of IR light by noting the IR illuminated dust particles. The marksmen can then discern the position of the targets, and again a surprise appearance of a target is minimised. Thus, this later variation of night shooting has been unable to simulate real, combat like training. An example of a night shooting training apparatus of this type is disclosed in UK patent application GB 2067237. Another example is disclosed in U.S. Pat. No. 4,336,018.
In an attempt to provide more realistic combat training, it has been proposed that the trainee marksmen wear goggles or use thermal or IR equivalent sensing devices that remove the effects of ambient light that may otherwise partially illuminate the targets. In such cases, the targets are thermally heated and the trainee marksmen are able to discern the particular targets by the thermal response of the IR night vision imaging equipment. In such cases, the targets have been heated by wrapping the targets in a warm blanket. The targets are usually lowered to a position where they are out of view while they are heated by the blankets. When the target is to be placed in a position to be seen by the trainee marksmen, the blankets are removed and the targets held upright. The residual heat is then able to be detected by the IR night vision imaging equipment by virtue of the thermal output in the IR spectrum radiating from the target itself. This recent proposal is particularly useful in the case of providing targets that simulate offensive vehicles such as tanks or armoured personnel carriers. Such a system however, has enormous practical problems in heating the blankets, wrapping the targets in the blankets, removing the blankets, and subsequently erecting the targets into an upright position where they can be viewed. Typically, many personnel are required to effect the necessary heating of the targets in this way, and on a particular range there may be many such targets required. Thus, there is a problem of providing personnel in the target range firing area for each of the targets.
In a variation of the above proposal, electric heating elements have been placed into the target materials or onto the surface of the target itself to be heated by an electric current. A problem with such an arrangement is that one projectile can break the electric continuity of the heating circuit and thus the heating effect is destroyed immediately by a single penetration of the target.
There is thus a need for a practical and cost effective target practice assembly for training marksman in the use of night vision equipment. Such a system could be used in complete darkness or even in low light conditions.
This need can be met with a system based on infrared (IR) projection and associated imaging equipment such as goggles, binoculars, monoculars, and/or weapon sights. A cost effective system must take into account and balance both the current and possible future costs of IR projectors.
The terminology of night vision technologies can become confusing because it is sometimes loosely defined. For purposes of this specification the following terminology will be used.
Night vision technologies can be broadly divided into four main categories; normal night vision, image intensification, active illumination, and thermal imaging. All four are defined below although this specification will focus more on the last three.
Normal Night Vision:
Usually refers to binoculars or telescopes with a large diameter objective. Large lenses can gather and concentrate light, thus intensifying light with purely optical means and enabling the user to see better in the dark than with the naked eye alone. Often night glasses also have a fairly large exit pupil of 7 mm or more to let all gathered light into the user's eye.
Image Intensification:
Image intensification technologies (sometimes called light amplification) work on the principle of magnifying the amount of received photons from various natural sources such as starlight or moonlight that is not intense enough for the human eye to see unaided.
Active Illumination:
Active illumination technologies work on the principle of coupling imaging intensification technology with an active source of illumination (projectors) in various infrared bands. Active illumination is an aspect of the invention described herein.
Thermal Imaging:
Thermal imaging technologies work by detecting the temperature difference between background and foreground objects and usually does not require any other source of illumination. However.
Infrared systems can be divided into three spectral regions—near, mid, and far infrared. These are usually abbreviated as NIR, MIR, and FIR. Today's reality is that MIR/FIR projection systems are considerably more expensive than NIR projection systems. But MIR/FIR projection systems can be used with lower tech and less expensive imaging intensifying night vision goggles, binoculars, monoculars, and/or weapon sights. It should also be noted that thermal imaging technologies operate in the far infrared (FIR) and can thus be used in conjunction with FIR projections systems in an active illumination situation.
In this disclosure the term night vision imaging equipment will be used to refer to equipment such as for example goggles, binoculars, monoculars, and/or weapon sights used by individuals during training. This disclosure will focus primarily on image intensification systems and thermal imaging systems. Image intensification (also called sometimes II technologies and sometimes called light amplification) has evolved into a wide range of capabilities, each with different performance capability and cost. The lower levels are less expensive than thermal imaging. The higher levels can be as expensive as thermal imaging systems.
Most image intensification systems are not usable in daylight because all light wavelengths flood the viewfinder presenting a whiteout effect. But this might be addressed in future systems with added selected light wavelength filters.
Most near infrared (NIR) projection systems should be compatible with most image intensifying night vision equipment (goggles, binoculars, monoculars, and/or weapon sights) now available. If the particular NIR projection system chosen for this application is not completely compatible with standard image intensifying night vision equipment then modified image intensifying night vision equipment tailored to the particular NIR projector will be used. We refer to that as “modified” night vision equipment. The invention of this disclosure anticipates that several combinations of IR projector technologies in combination with multiple versions of night vision equipment might be used.